A complementary metal oxide semiconductor (CMOS) image sensor may have a photodiode and a metal oxide semiconductor (MOS) transistor formed in a unit pixel. A CMOS image censor may sequentially detect an electrical signal of each unit pixel through switching to produce an image.
A related art CMOS image sensor may be configured with a horizontally disposed photodiode and transistor. A related art horizontally disposed CMOS image sensor may overcome various limitations of a charge-coupled device (CCD) image sensor. The related art horizontal CMOS sensor, however, still has limitations.
For example, a related art horizontal CMOS image sensor may be manufactured with a photodiode and transistor disposed in mutual horizontal positions and proximity. Accordingly, when additional space for a photodiode is required, a fill factor region should be reduced, and limits may be imposed on resolution potential.
In addition, it may be difficult to attain ideal conditions for simultaneous production of photodiodes and transistors for a related art horizontal CMOS image sensor.
Further, in a horizontal CMOS image sensor according to the related art, a resolution of an image sensor may be reduced when a pixel size increases, and sensitivity of the image sensor may be reduced when an area of the photodiode is reduced.